This invention relates, in general, to superconductors, and more particularly, to an electrically switched superconductor.
Originally, superconductivity was confined to materials which required very low temperatures, e.g. less than 20.degree. K. These materials were extensively studied, some are produced in commercial quantities, and a detailed theory was developed to explain the loss of electrical resistance that these materials exhibited. This theory is known as the BCS theory and won the Nobel prize. The BCS theory showed that phonons that somehow coupled themselves to electrons could cause a complete disappearance of resistance, as well as a number of other effects. A phonon is a vibrational wave in a solid, and it is viewed as a particle having an energy, a sort of momentum, and a wave length. Phonons come in two species, both of which have their own distinct range of energies, etc. Acoustic phonons are what carry heat and sound through a solid. They generally have lower energy and move at or below the speed of sound, i.e., the speed of sound in the solid. Optical phonons have somewhat higher energies, and generally do not overlap the energy range of acoustic phonons.
More recently, all of the same effects observed in the original superconductors have been observed in newly discovered ceramic superconductors which have a much higher transition temperature, that is, above 77.degree. K. This temperature is high enough to permit conventional semiconductor circuits to function, and so permits semiconductor devices and superconductor films to be used together.
With the discovery of these superconductors it is apparent that it would be desirable to be able to electrically switch the superconductor to a non-superconductor without having to increase the temperature of the material.
Accordingly, it is an object of the present invention to provide means for electrically switching a superconductor without increasing the temperature of the superconductor.
Another object of the present invention is to rapidly switch a superconductor back and forth between being a superconductor and a non-superconductor.
A further object of the present invention is to be able to control superconducting properties at a high speed while using low power.